Kimi Raikkonen warned Ferrari will need time to challenge Mercedes in every race but predicted the Italian team will pounce when tracks and conditions are advantageous throughout the season.

Mercedes have won two Formula One races so far this year, while Raikkonen's Ferrari team-mate Sebastian Vettel managed to upset Lewis Hamilton and Nico Rosberg at the Malaysia Grand Prix.

Hamilton and Rosberg's return to first and second in Shanghai on Sunday was interpreted by many as proof Ferrari's success in Malaysia was a one-off, but Raikkonen is not convinced.

The Finnish driver argued on Monday that Ferrari can catch Mercedes this year, while he wants team principal Maurizio Arrivabene and his staff to identify and exploit races that suit their cars.

"Like Seb showed, we could win but obviously it depends," Raikkonen told Autosport.

"One circuit can be good for one team and the next can be a different story.

"We have to be up there. When something happens to them [Mercedes] or conditions change, we have to be there.

"I feel - with the speed - we will get there so we can regularly try to beat them in any conditions or at any circuit, but we need some more time."

When pressed on whether he believes Ferrari can truly challenge Mercedes in 2015, Raikkonen said: "Yes. I don't see a reason why not.

"I think we have good plans already since last year and made big gains and will make big gains during this year.

"Everybody improves and it depends what the rest are doing but we trust the way our team is working altogether and what we are doing.

"So it definitely shows we are going the right way and doing the right things but you need time - you cannot make miracles overnight."

After retiring in the season opener in Australia, Raikkonen has finished fourth in Malaysia and China, ensuring Mercedes and Ferrari held a monopoly of the top-four positions.

But the 2007 F1 champion believes if he can improve he can eliminate errors in practice and qualifying, he could go even better at this week's Bahrain GP.

"We go there, try to do our best and try to clean up Friday and Saturday," Raikkonen said.